Sources of nitrogen and phosphorus supporting the growth of bacteria and phytoplankton in an oligotrophic Canadian shield lake

We used a dilution gradient technique to determine the relative importance of N and P derived from the dissolved pool, storage, and recycling by planktonic consumers to the growth of bacteria and algae in an oligotrophic lake. Recycling was the dominant source of N for both algae and bacteria and the dominant source of P for bacteria. However, storage was an important source of P for algae early in the year, but P recycling was a dominant source for algae late in the year. Models of nutrient flux in the microbial and classic food webs must be combined in a manner consistent with the integrated nature of these fluxes.